Method for preparing fiber composite magnetic microparticles and use thereof as a biological carrier

Abstract

The application discloses a kind of fiber composite magnetic microparticle preparation method and its application as biological carrier, it is related to biological filler technical field, and its technical scheme main points include following steps: (1) Fe3O4 Magnetic particles are added to the reactor with pure water, ultrasonic treatment, nitrogen protection is used Mechanical stirring homogenization;(2) at 35-55 ℃, modifier and surfactant are added to the system, and aging;(3) drop the mixed monomer solution of styrene, crosslinking agent and epoxy monomer to the system;(4) after drop end, add fiber, stir evenly;(5) after stirring evenly, initiator is added to the system, and temperature is raised to 65-85 ℃, and keep warm under stirring;(6) filtration, obtain fiber composite magnetic microparticle, wash with pure water and ethanol, and vacuum drying to constant weight;The above fiber composite magnetic microparticle is hydrolyzed modification or chelated metal particles after hydrolysis, and is applied to aerobic or anaerobic biological water treatment as biological carrier.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biological filler, more particularly, it relates to a preparation method of fiber composite magnetic microparticles and application thereof as a biological carrier. BACKGROUND

[0002] Biological treatment is the mainstream technology of wastewater treatment, among which, the biological membrane method based on biological filler is widely used in urban sewage, aquaculture wastewater, chemical wastewater and other fields. Its characteristics are that microorganisms attach to filter material or some carriers to grow and reproduce, and form a membrane-shaped biological sludge. The biological membrane intercepts the microorganisms with pollutant removal function, reduces the loss of functional microorganisms, and provides certain protection for them. Magnetic filler has been widely concerned due to its high surface area and recyclability. The surface properties of the filler, such as hydrophilicity, roughness, porosity, specific surface area, surface charge and the like, are important factors affecting the adsorption and immobilization of microorganisms.

[0003] The existing patent application file with the application publication number CN 113104959 A discloses a magnetic silica particle. The magnetic particles in the core have a shell structure. The silica in the shell can protect the magnetic particles from oxidation and dissolution, prolonging the service life. It is applied to wastewater treatment, which can significantly improve the removal of ammonia nitrogen and chemical oxygen demand COD. However, this research does not characterize the biological affinity.

[0004] The existing patent application file with the application publication number CN 104609567 A discloses a hydrophilic magnetic suspended biological filler and a preparation method thereof. By adding composite magnetic powder, glue powder, zeolite powder, slag powder, polyethylene and the like, and after extrusion molding, mechanical opening, short wave ultraviolet light irradiation and crushing, a hydrophilic suspended biological carrier is prepared. However, the processing technology is complex and the cost is high.

[0005] The above existing technologies do not solve the problem of biological affinity as a carrier. SUMMARY

[0006] In view of the deficiencies of the prior art, the first purpose of the present application is to provide a preparation method of fiber composite magnetic microparticles, and the second purpose is to provide the application of the fiber composite magnetic microparticles. The fiber composite magnetic microparticles after treatment solve the problem of biological affinity as a carrier.

[0007] To achieve the above-mentioned first purpose, the present application provides the following technical scheme: a preparation method of fiber composite magnetic microparticles, comprising the following steps:

[0008] (1) Add ferroferric oxide magnetic particles into a reactor containing pure water, and ultrasonic treat for 15-30 min. Under the protection of nitrogen, use mechanical stirring for homogenization;

[0009] (2) At 35-55℃, a modifier and a surfactant are added to the system, and aged for 2h;

[0010] (3) Then a mixed monomer solution of styrene, crosslinking agent and epoxy-based monomer is added dropwise to the system;

[0011] (4) After the completion of the dropwise addition of the above mixed monomer solution, fibers are added and stirred uniformly;

[0012] (5) After stirring uniformly, an initiator is added to the system, and the temperature is raised to 65-85℃, and kept for 3-6h under stirring;

[0013] (6) Filtration is performed for solid-liquid separation, and the fiber composite magnetic microparticles are washed with pure water and ethanol, and vacuum dried to constant weight.

[0014] Further, the mass ratio of the modifier to the ferroferric oxide magnetic particles is 1:1-1.5:1.

[0015] Further, based on the total mass of the mixed monomer solution of styrene, crosslinking agent and epoxy-based monomer, the amount of styrene is 60-80%, the amount of crosslinking agent is 10-20%, and the amount of epoxy-based monomer is 10-20%.

[0016] Further, the fiber diameter is 1-10μm, and the fiber length is 300-1000μm.

[0017] Further, the mass ratio of the fiber to the mixed monomer solution is 1:200-1:5.

[0018] Further, the fiber composite magnetic microparticles prepared above are hydrolyzed and modified, including the following steps:

[0019] The dried fiber composite magnetic microparticles are added to the reactor, a hydrolysis agent is added to the system, mechanical stirring is used, and hydrolysis is performed at 70-90℃ for 0.5-6h; filtration is performed to obtain the hydrolyzed and modified fiber composite magnetic microparticles, which are washed with pure water and ethanol, and vacuum dried to constant weight.

[0020] Further, the mass concentration of the hydrolysis agent is 1-20%.

[0021] Further, the hydrolysis agent includes one or more of sodium hydroxide, potassium hydroxide, water glass, sodium phosphate, potassium phosphate, and sodium sulfide.

[0022] Further, the fiber composite magnetic microparticles are modified by chelating metal ions, including the following steps:

[0023] The hydrolyzed and dried fiber composite magnetic microparticles are added into a reactor, a metal salt solution is added into the system, and stirring is performed at room temperature for 2-5 hours; filtration is performed to obtain fiber composite magnetic microparticles after hydrolysis and modification and chelation of metal ions, and the fiber composite magnetic microparticles are washed with pure water and ethanol and vacuum dried until a constant weight is obtained.

[0024] Further, the metal salt solution comprises one or more of ferric chloride, ferric sulfate, ferrous chloride, ferrous sulfate, copper chloride, copper sulfate, nickel chloride, nickel sulfate, manganese chloride, and manganese sulfate.

[0025] Further, the mass concentration of the metal salt solution is 1-20%, and the mass ratio of the metal salt solution to the fiber composite magnetic microparticles is (200-5):1.

[0026] To achieve the second object, the application provides the following technical scheme.

[0027] The application provides application of fiber composite magnetic microparticles or modified microparticles thereof as carriers in treatment of wastewater in an aerobic activated sludge reactor.

[0028] 1) In the activated sludge reactor, 1-20 g / L of aerobic activated sludge and fiber composite magnetic microparticles or modified microparticles with a concentration of 1-20 g / L are added, and the air flow is controlled to be 200 mL / min by a gas rotor flow meter.

[0029] 2) The reactor is operated in a sequencing batch mode, one cycle is 12 hours, aeration is performed for 11 hours in each cycle, sedimentation is performed for 30 minutes, and drainage and water feeding are performed for 30 minutes; 500 mL of supernatant is discharged each time, 490 mL of tap water and 10 mL of simulated wastewater concentrate are added; the simulated wastewater concentrate is prepared from ammonium chloride and sodium acetate, the ammonia nitrogen concentration of the simulated wastewater concentrate is 5 g / L, and the COD concentration is 50 g / L.

[0030] 3) The reactor is continuously operated for 10 days, the COD and ammonia nitrogen concentrations in the supernatant are measured before drainage in each cycle, 50 mL of sludge is taken out after 10 days to measure the oxygen consumption rate, and the aerobic activated sludge on the surface of the fiber composite magnetic microparticles or modified microparticles is observed after 10 days.

[0031] The application provides application of fiber composite magnetic microparticles or modified microparticles thereof as carriers in treatment of wastewater in an anaerobic activated sludge reactor.

[0032] 1) In the sequencing batch reactor, 5-40 g / L of anaerobic activated sludge and fiber composite magnetic microparticles or modified microparticles with a concentration of 1-15 g / L are added, a intermittent stirring device is used for stirring, the stirring frequency is 30 s per 5 min, and the temperature is controlled to be 35±1 ℃.

[0033] 2) in a sequencing batch mode, 12h as a cycle; 11h aeration, 30min sedimentation, 30min drainage, water feeding operation; 100mL supernatant is discharged each time, 97.5mL tap water, 2.5mL simulated wastewater concentrate are added; wherein, the simulated wastewater concentrate is prepared by potassium nitrate and sodium acetate, the nitrate nitrogen concentration of the simulated wastewater concentrate is 5g / L, and the COD concentration is 50g / L;

[0034] 3) continuous operation for 30 days, sampling before drainage every day, testing the sedimentation performance and COD removal effect of the anaerobic activated sludge, and observing the anaerobic activated sludge on the surface of the fiber-composite magnetic microparticle or the modified microparticle after 30 days.

[0035] In summary, the fiber-composite magnetic microparticle has the following beneficial effects: the fiber length of the fiber-composite magnetic microparticle is greater than that of the magnetic microparticle, the fiber-composite magnetic microparticle can extend the velvet-like protrusions on the surface of the carrier, and the specific surface area of the magnetic microparticle is improved; the fibers on the surface of the fiber-composite magnetic microparticle are hydrolyzed to form hydrophilic groups such as carboxyl groups, and the hydrophilic groups of the fibers are exposed, so that the hydrophilization modification of the magnetic microparticle is realized, and the biological affinity of the magnetic microparticle is improved; the hydrolyzed fibers on the surface of the fiber-composite magnetic microparticle are chelated with metal ions, so that the biological affinity of the magnetic microparticle is further improved, and the electron transfer efficiency between microorganisms in the activated sludge is promoted; the fiber-composite magnetic microparticle or the modified microparticle is applied to wastewater treatment, the biofilm formation speed is improved, the degradation of COD and ammonia nitrogen in the aerobic system is promoted, and the removal rate of COD and nitrate in the anaerobic system is promoted. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a fiber-composite magnetic microparticle structure diagram of the application, wherein, A: fiber-composite magnetic microparticle, B: hydrolysis-modified fiber-composite magnetic microparticle, C: fiber-composite magnetic microparticle hydrolyzed and chelated with metal particles;

[0037] Figure 2 is a microscope diagram of the fiber-composite magnetic microparticle prepared in example 1;

[0038] Figure 3 is a scanning electron microscope diagram of the magnetic microparticle prepared in comparative example 1;

[0039] Figure 4 is a fluorescence microscope diagram of the biofilm of the magnetic microparticle after 3 days, wherein, (a): the fiber-composite magnetic microparticle prepared in example 1, (b): the hydrolysis-modified fiber-composite magnetic microparticle prepared in example 3, (c): the magnetic microparticle prepared in comparative example 1. DETAILED DESCRIPTION

[0040] In some embodiments, the modifier is selected from one or more of oleic acid, tartaric acid, gamma-aminotriethoxysilane, gamma-glycidoxypropyltrimethoxysilane, vinyltriethoxysilane, vinyltrichlorosilane, and gamma-aminotrimethoxysilane.

[0041] In some embodiments, the surfactant is selected from one or more of sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecyl benzene sulfonate, sodium laurate, and sodium oleate. More preferably, the surfactant is selected from one or more of sodium dodecyl sulfate, sodium dodecyl sulfonate, and sodium dodecyl benzene sulfonate.

[0042] In some embodiments, the crosslinking agent is selected from one or more of divinylbenzene, N,N-methylenebisacrylamide, pentaerythritol triacrylate, ethylene glycol dimethacrylate, and pentaerythritol tetraacrylate.

[0043] In some embodiments, the epoxy monomer is selected from one or more of allyl glycidyl ether, glycidyl methacrylate, and glycidyl acrylate.

[0044] In some embodiments, the fiber is selected from one or more of polyester fiber, polyvinyl alcohol fiber, polyamide fiber, polyacrylonitrile fiber, polypropylene fiber, and polyvinyl chloride fiber.

[0045] In some embodiments, the initiator is selected from one or more of azobisisobutyronitrile, dibenzoyl peroxide, dodecanoyl peroxide, azobisisoheptane nitrile, potassium persulfate, and ammonium persulfate.

[0046] The application is further described in detail below with reference to the following examples.

[0047] Example 1

[0048] (1) Preparation of fiber-composite magnetic microparticles

[0049] Fe3O4magnetic particles 35 g were added to a 250 mL four-neck flask containing 100 g of pure water, and ultrasonically treated for 30 min. Under nitrogen protection, the system was heated to 55°C and mechanically stirred for 30 min. Then, 35 g of oleic acid and 0.1 g of sodium dodecyl sulfate were added to the system, which was heated to 65°C and aged for 2 h. Then, a mixed solution of 75 g of styrene, 15 g of divinylbenzene, and 15 g of glycidyl methacrylate was added dropwise to the system. After the dropwise addition of the mixed solution was completed, 0.7 g of polyester fiber with a length of 350 μm and a diameter of 2 μm was added, and the system was stirred uniformly. Then, 6 g of azobisisobutyronitrile was added as an initiator, and the system was incubated for 3 h. The fiber-composite magnetic microparticles were obtained by filtration, washed with pure water and ethanol, and vacuum dried to constant weight.

[0050] (2) Biofilm formation and pollutant removal experiment of the aerobic wastewater treatment system

[0051] In a 1000 mL activated sludge reactor, 800 mL of aerobic activated sludge with a suspended solid content of 5000 mg / L was added, 3.6 g of the fiber-composite magnetic microparticles obtained in step (1) above was added, and the gas flow was controlled at 200 mL / min by a gas rotameter. The reactor was operated in a sequencing batch mode, with a cycle of 12 h, 11 h of aeration, 30 min of sedimentation, and 30 min of water discharge and water feeding. Each time, 500 mL of water was discharged, 490 mL of water was fed, and 10 mL of simulated wastewater concentrate was added at the beginning of each cycle, with the ammonia nitrogen concentration of the simulated wastewater concentrate being 5 g / L and the COD concentration being 50 g / L. The reactor was continuously operated for 10 days, and the COD and ammonia nitrogen concentrations in the supernatant were measured before water discharge in each cycle. After 10 days, 50 mL of sludge was taken to measure the oxygen consumption rate, and the aerobic activated sludge on the surface of the fiber-composite magnetic microparticles was observed.

[0052] (3) Biofilm formation and pollutant removal experiment of the anaerobic wastewater treatment system

[0053] In a 250 mL sequencing batch reactor, anaerobic activated sludge and fiber-composite magnetic microparticles were inoculated, and a intermittent stirring device was used for stirring, with a stirring frequency of 30 s for 5 min, and the temperature was controlled at 35±1℃. The reactor was operated in a sequencing batch mode, with a cycle of 12 h. Each cycle included 11 h of aeration, 30 min of sedimentation, and 30 min of water discharge and water feeding. Each time, 100 mL of water was discharged, 97.5 mL of water was fed, and 2.5 mL of simulated wastewater concentrate was added at the beginning of each cycle, with the nitrate nitrogen concentration of the simulated wastewater concentrate being 5 g / L and the COD concentration being 50 g / L. The reactor was continuously operated for 30 days, and the settling performance and COD removal effect of the anaerobic activated sludge were tested before water discharge every day. After 30 days, the anaerobic activated sludge on the surface of the fiber-composite magnetic microparticles was observed.

[0054] Example 2

[0055] (1) Preparation of fiber-composite magnetic microparticles

[0056] Fe3O4magnetic particles 35 g were taken and added to a 250 mL four-necked flask containing 100 g of pure water, and ultrasonic treatment was performed for 30 min. Under nitrogen protection, mechanical stirring was used for heat preservation at 55℃ for 30 min. Then, 35 g of oleic acid and 0.1 g of sodium dodecyl sulfate were added to the system, the temperature was raised to 65℃, and aging was performed for 2 h. Then, a mixed solution of 75 g of styrene, 15 g of divinylbenzene, and 15 g of glycidyl methacrylate was added dropwise to the system. After the dropwise addition of the mixed solution was completed, 0.7 g of polyvinyl alcohol fiber with a length of 400 μm and a diameter of 2 μm was added, and stirring was performed uniformly. Then, 6 g of dibenzoyl peroxide was added as an initiator, and heat preservation was performed for 3 h. Filtration was performed, and the fiber-composite magnetic microparticles were washed with pure water and ethanol, and vacuum dried to constant weight.

[0057] (2) Aerobic wastewater treatment system of biofilm and pollutant removal experiment

[0058] In 1000 mL activated sludge reactor, 800 mL of aerobic activated sludge with suspended solid content of 5000 mg / L was added, 3.6 g of fiber composite magnetic microparticles obtained in step (1) was added, and the gas flow was controlled by a gas rotor flowmeter at 200 mL / min. It was operated in a sequencing batch mode, 12 h as a cycle, 11 h aeration per cycle, 30 min sedimentation, 30 min drainage, water feeding and other operations. Each time 500 mL of water was drained, 490 mL of water was fed, and 10 mL of simulated wastewater concentrate was added per cycle, wherein the ammonia nitrogen concentration of the simulated wastewater concentrate was 5 g / L, and the COD concentration was 50 g / L. Continuous operation for 10 days, sampling before drainage per cycle to determine the COD and ammonia nitrogen concentration in the supernatant, 50 mL of sludge was taken after 10 days to determine the oxygen consumption rate, and the aerobic activated sludge on the surface of the fiber composite magnetic microparticles was observed after 10 days.

[0059] (3) Anaerobic wastewater treatment system of biofilm and pollutant removal experiment

[0060] In a 250 mL sequencing batch reactor, anaerobic activated sludge and fiber composite magnetic microparticles were added, intermittent stirring device was used for stirring, stirring frequency was 30 s for 5 min, and temperature was controlled at 35±1℃. It was operated in a sequencing batch mode, 12 h as a cycle. Each cycle was aerated for 11 h, and 30 min of sedimentation was performed, and 30 min of drainage, water feeding and other operations were performed. Each time 100 mL of water was drained, 97.5 mL of water was fed, and 2.5 mL of simulated wastewater concentrate was added per cycle, wherein the nitrate nitrogen concentration of the simulated wastewater concentrate was 5 g / L, and the COD concentration was 50 g / L. Continuous operation for 30 days, sampling before drainage every day to test the settling performance and COD removal effect of anaerobic activated sludge, and observing the anaerobic activated sludge on the surface of the fiber composite magnetic microparticles after 30 days.

[0061] Example 3

[0062] (1) Preparation of fiber composite magnetic microparticles

[0063] Take four iron oxide magnetic particles 35 g into a 250 mL four-necked flask containing 100 g of pure water, ultrasonic treatment for 30 min, under nitrogen protection, at 55°C, using mechanical stirring for 30 min, add tartaric acid 40 g and sodium dodecyl sulfate 0.1 g to the system, heat to 65°C, and age for 2 h, then add a mixed solution of 75 g of styrene, 15 g of divinylbenzene and 15 g of glycidyl methacrylate dropwise, after the dropwise addition of the mixed solution is completed, add polyvinyl alcohol fibers with a length of 350 μm and a diameter of 2 μm 0.7 g, stir uniformly, add initiator peroxide dodecanoyl 6 g, and incubate for 3 h, filter, and obtain fiber composite magnetic particles, which are washed with pure water and ethanol and vacuum dried to constant weight.

[0064] (2) Hydrolysis modification of fiber composite magnetic particles

[0065] Add 100 g of the fiber composite magnetic particles obtained in step (1) above to a reactor, add 100 g of a 15% mass concentration sodium hydroxide solution, use mechanical stirring, and hydrolyze at 80°C for 3 h; filter to obtain hydrolyzed fiber composite magnetic particles, which are washed with pure water and ethanol and vacuum dried to constant weight.

[0066] (3) Biofilm formation and pollutant removal experiment of aerobic wastewater treatment system

[0067] In a 1000 mL activated sludge reactor, add 800 mL of aerobic activated sludge with a suspended solid content of 5000 mg / L, add 3.6 g of the hydrolyzed modified fiber composite magnetic particles obtained in step (2), and control the gas flow to be 200 mL / min through a gas rotor flowmeter. Run in a sequencing batch mode, with a cycle of 12 h, aeration for 11 h per cycle, settling for 30 min, and 30 min for drainage and water feeding operations. Drain 500 mL each time, and feed 490 mL of water, with an initial addition of 10 mL of simulated wastewater concentrate per cycle, wherein the ammonia nitrogen concentration of the simulated wastewater concentrate is 5 g / L, and the COD concentration is 50 g / L. Run continuously for 10 days, measure the COD and ammonia nitrogen concentrations in the supernatant before drainage per cycle, measure the oxygen consumption rate of 50 mL of sludge after 10 days, and observe the aerobic activated sludge on the surface of the fiber composite magnetic particles after 10 days.

[0068] (4) Biofilm formation and pollutant removal experiment of anaerobic wastewater treatment system

[0069] In a 250 mL sequencing batch reactor, inoculate anaerobic activated sludge and hydrolysis modified fiber composite magnetic microparticles obtained in step (2) are added, and a intermittent stirring device is used for stirring, the stirring frequency is 5 min stirring 30 s, the temperature is controlled at 35 ± 1 ℃. Run in a sequencing batch mode, 12 h as a cycle. 11 h aeration, 30 min sedimentation, 30 min drainage, water feeding and other operations. Drainage 100 mL each time, water feeding 97.5 mL, initial addition of simulated wastewater concentrate 2.5 mL per cycle, the nitrate nitrogen concentration of the simulated wastewater concentrate is 5 g / L, and the COD concentration is 50 g / L. Run continuously for 30 days, take samples before drainage every day, test the settling performance and COD removal effect of anaerobic activated sludge, and observe the surface anaerobic activated sludge of the fiber composite magnetic microparticles after 30 days.

[0070] Example 4

[0071] (1) Preparation of fiber composite magnetic microparticles

[0072] Take 35 g of ferroferric oxide magnetic particles and add them to a 250 mL four-necked flask containing 100 g of pure water, ultrasonic treatment for 30 min, under nitrogen protection, at 55 ℃, use mechanical stirring for 30 min, add 35 g of oleic acid and 0.1 g of sodium dodecyl sulfate to the system, heat to 65 ℃, and age for 2 h, then add a mixed solution of 75 g of styrene, 15 g of pentaerythritol triacrylate and 15 g of allyl glycidyl ether to the system, after the completion of the dropwise addition of the mixed solution, add 0.7 g of polyamide fiber with a length of 450 μm and a diameter of 3 μm, stir uniformly, add 6 g of azobisisheptylnitrile initiator, and heat for 3 h, filter, wash with pure water and ethanol, and vacuum dry to constant weight.

[0073] (2) Hydrolysis modification of fiber composite magnetic microparticles

[0074] Add 100 g of fiber composite magnetic microparticles obtained in step (1) to a reactor, add 150 g of 5% mass concentration potassium hydroxide solution, use mechanical stirring, hydrolyze at 80 ℃ for 2 h; filter, obtain hydrolyzed fiber composite magnetic microparticles, wash with pure water and ethanol, and vacuum dry to constant weight.

[0075] (3) Biofilm formation and pollutant removal experiment of aerobic wastewater treatment system

[0076] In a 1000 mL activated sludge reactor, 800 mL of aerobic activated sludge with a suspended solid content of 5000 mg / L was added, and 3.6 g of the hydrolysis-modified fiber-composite magnetic microparticles obtained in step (2) was added, and the gas flow was controlled at 200 mL / min by a gas rotor flow meter. The reactor was operated in a sequencing batch mode, with 12 h as one cycle, 11 h of aeration, 30 min of sedimentation, and 30 min of water discharge and water feeding. Each time, 500 mL of water was discharged, and 490 mL of water was fed, and 10 mL of simulated wastewater concentrate was added in each cycle, with the ammonia nitrogen concentration of the simulated wastewater concentrate being 5 g / L and the COD concentration being 50 g / L. The reactor was continuously operated for 10 days, and the COD and ammonia nitrogen concentrations in the supernatant were measured before water discharge in each cycle. After 10 days, 50 mL of sludge was taken to measure the oxygen consumption rate, and the aerobic activated sludge on the surface of the fiber-composite magnetic microparticles was observed.

[0077] (4) Biofilm formation and pollutant removal experiment of the anaerobic wastewater treatment system

[0078] In a 250 mL sequencing batch reactor, anaerobic activated sludge and the hydrolysis-modified fiber-composite magnetic microparticles obtained in step (2) were added, and a intermittent stirring device was used for stirring, with a stirring frequency of 30 s for 5 min, and the temperature was controlled at 35±1℃. The reactor was operated in a sequencing batch mode, with 12 h as one cycle. Each cycle included 11 h of aeration, 30 min of sedimentation, and 30 min of water discharge and water feeding. Each time, 100 mL of water was discharged, and 97.5 mL of water was fed, and 2.5 mL of simulated wastewater concentrate was added in each cycle, with the nitrate nitrogen concentration of the simulated wastewater concentrate being 5 g / L and the COD concentration being 50 g / L. The reactor was continuously operated for 30 days, and the settling performance and COD removal effect of the anaerobic activated sludge were tested before water discharge every day, and the anaerobic activated sludge on the surface of the fiber-composite magnetic microparticles was observed after 30 days.

[0079] Example 5

[0080] (1) Preparation of fiber-composite magnetic microparticles

[0081] Fe3O4magnetic particles 35 g were taken into a 250 mL four-necked flask containing 100 g of pure water, and ultrasonic treatment was performed for 30 min. Under nitrogen protection, mechanical stirring was performed at 55℃ for 30 min, and then vinyltriethoxysilane 35 g and sodium dodecyl sulfate 0.1 g were added to the system. The temperature was raised to 65℃, and aging was performed for 2 h. Then a mixed solution of 75 g of styrene, 15 g of pentaerythritol triacrylate, and 15 g of glycidyl methacrylate was added dropwise to the system, and after the dropwise addition was completed, 0.7 g of polyacrylonitrile fiber with a length of 500 μm and a diameter of 4 μm was added, and stirring was performed uniformly. Then 6 g of initiator potassium persulfate was added, and the temperature was maintained for 3 h. Filtration was performed, and the fiber-composite magnetic microparticles were washed with pure water and ethanol, and vacuum dried to constant weight.

[0082] (2) Hydrolysis modification of the fiber-composite magnetic microparticles

[0083] 100 g of the fiber-composite magnetic microparticles obtained in step (1) were added to a reactor, 200 g of a 10% sodium hydroxide solution was added, and mechanical stirring was used to hydrolyze at 80°C for 6 h. Filtration was performed to obtain the hydrolyzed fiber-composite magnetic microparticles, which were washed with pure water and ethanol and vacuum dried to constant weight.

[0084] (3) Bioaffinity modification of the fiber-composite magnetic microparticles by chelating metal ions

[0085] 20 g of the hydrolyzed and modified fiber-composite magnetic microparticles obtained in step (2) were added to a reactor, 500 g of a 15% copper chloride solution was added to the system, and stirring was performed at room temperature for 2-5 h. Filtration was performed to obtain the hydrolyzed and modified fiber-composite magnetic microparticles chelating metal ions, which were washed with pure water and ethanol and vacuum dried to constant weight.

[0086] (4) Biofilm formation and pollutant removal experiment of the aerobic wastewater treatment system

[0087] In a 1000 mL activated sludge reactor, 800 mL of aerobic activated sludge with a suspended solid content of 5000 mg / L was added, and 3.6 g of the hydrolyzed and modified fiber-composite magnetic microparticles chelating metal ions obtained in step (3) was added. The gas flow was controlled at 200 mL / min by a gas rotor flowmeter. Sequential batch operation was performed, with 11 h of aeration and 30 min of sedimentation per cycle, and 30 min of water discharge and water feeding. Each time, 500 mL of water was discharged, and 490 mL of water was fed. The initial addition of simulated wastewater concentrate was 10 mL per cycle, with an ammonia nitrogen concentration of 5 g / L and a COD concentration of 50 g / L. The experiment was continuously operated for 10 days, and the COD and ammonia nitrogen concentrations in the supernatant were measured before water discharge each cycle. After 10 days, 50 mL of sludge was taken to measure the oxygen consumption rate, and the aerobic activated sludge on the surface of the fiber-composite magnetic microparticles was observed after 10 days.

[0088] (5) Biofilm formation and pollutant removal experiment of the anaerobic wastewater treatment system

[0089] In a 250 mL sequencing batch reactor, inoculate anaerobic activated sludge and the hydrolysis modified and metal ion chelated fibrous composite magnetic microparticles obtained in step (3) are added, and a intermittent stirring device is used for stirring, with a stirring frequency of 30 s for 5 min, and the temperature is controlled at 35 ± 1 ℃. Run in a sequencing batch mode, 12 h for a cycle. Aeration for 11 h per cycle, settling for 30 min, and 30 min for drainage, water feeding, etc. Drainage of 100 mL each time, water feeding of 97.5 mL, and initial addition of simulated wastewater concentrate of 2.5 mL per cycle, wherein the simulated wastewater concentrate has a nitrate nitrogen concentration of 5 g / L and a COD concentration of 50 g / L. Run continuously for 30 days, and take samples before drainage every day to test the settling performance of the anaerobic activated sludge and the COD removal effect, and observe the anaerobic activated sludge on the surface of the fibrous composite magnetic microparticles after 30 days.

[0090] Example 6

[0091] (1) Preparation of fibrous composite magnetic microparticles

[0092] Take 35 g of ferroferric oxide magnetic particles and add them to a 250 mL four-necked flask containing 100 g of pure water, and ultrasonically treat for 30 min. Under nitrogen protection, heat to 55 ℃ and use mechanical stirring to keep the temperature for 30 min. Add 35 g of oleic acid and 0.1 g of sodium dodecyl sulfate to the system, and heat to 65 ℃. Age for 2 h, then add a mixed solution of 75 g of styrene, 15 g of ethylene glycol dimethacrylate, and 15 g of glycidyl acrylate dropwise to the system. After the dropwise addition of the mixed solution is completed, add 0.7 g of polyvinyl chloride fibers with a length of 200 μm and a diameter of 5 μm, stir uniformly, add 6 g of initiator ammonium persulfate, and keep the temperature for 3 h. Filter, wash with pure water and ethanol, and vacuum dry to constant weight.

[0093] (2) Hydrolysis modification of fibrous composite magnetic microparticles

[0094] Add 100 g of dried fibrous composite magnetic microparticles to a reactor, add 250 g of a 8% potassium hydroxide solution, and use mechanical stirring to hydrolyze at 80 ℃ for 4 h. Filter to obtain hydrolyzed fibrous composite magnetic microparticles, wash with pure water and ethanol, and vacuum dry to constant weight.

[0095] (3) Bioaffinity modification of fibrous composite magnetic microparticles by chelating metal ions

[0096] Take 20 g of hydrolysis modified fibrous composite magnetic microparticles obtained in step (2) and add them to a reactor. Add 400 g of a 10% ferrous sulfate solution to the system, and stir at room temperature for 2-5 h. Filter to obtain hydrolysis modified and metal ion chelated fibrous composite magnetic microparticles, wash with pure water and ethanol, and vacuum dry to constant weight.

[0097] (4) Aerobic wastewater treatment system of biofilm and pollutant removal experiment

[0098] In 1000 mL activated sludge reactor, 800 mL of suspended solid content of 5000 mg / L aerobic activated sludge was added, 3.6 g of hydrolysis modified and chelated metal ion after fiber composite magnetic microparticles were added, and the gas flow was controlled by gas rotor flow meter 200 mL / min. Run in a sequential batch mode, 12 h as a cycle, 11 h aeration, 30 min settling, 30 min drainage, water inlet and other operations. Each drainage 500 mL, water inlet 490 mL, initial addition of simulated wastewater concentrate 10 mL per cycle, the ammonia nitrogen concentration of simulated wastewater concentrate was 5 g / L, and the COD concentration was 50 g / L. Continuous operation for 10 days, the COD and ammonia nitrogen concentration in the supernatant were determined before drainage every cycle, 50 mL of sludge was taken after 10 days to determine the oxygen consumption rate, and the aerobic activated sludge on the surface of fiber composite magnetic microparticles was observed after 15 days.

[0099] (5) Anaerobic wastewater treatment system of biofilm and pollutant removal experiment

[0100] In 250 mL sequential batch reactor, inoculated anaerobic activated sludge and hydrolysis modified and chelated metal ion after fiber composite magnetic microparticles obtained in step (3) were added, intermittent stirring device was used for stirring, stirring frequency was 5 min stirring 30 s, temperature was controlled at 35±1℃. Run in a sequential batch mode, 12 h as a cycle. Each cycle aeration 11 h, 30 min settling, 30 min drainage, water inlet and other operations. Each drainage 100 mL, water inlet 97.5 mL, initial addition of simulated wastewater concentrate 2.5 mL per cycle, the nitrate nitrogen concentration of simulated wastewater concentrate was 5 g / L, and the COD concentration was 50 g / L. Continuous operation for 30 days, the settling performance and COD removal effect of anaerobic activated sludge were tested before drainage every day, and the anaerobic activated sludge on the surface of fiber composite magnetic microparticles was observed after 30 days.

[0101] Example 7

[0102] (1) Preparation of fiber composite magnetic microparticles

[0103] Take four iron oxide magnetic particles 35 g into a 250 mL four-necked flask containing 100 g of pure water, ultrasonic treatment for 30 min, under nitrogen protection, at 55°C, using mechanical stirring for 30 min, add γ-glycidyl ether propyl trimethoxysilane 35 g and sodium dodecyl sulfate 0.1 g to the system, heat to 65°C, and age for 2 h, then add a mixed solution of 75 g of styrene, 15 g of divinylbenzene and 15 g of allyl glycidyl ether to the system, after the completion of the dropwise addition of the mixed solution, add 0.7 g of polyamide fiber with a length of 400 μm and a diameter of 6 μm, stir uniformly, add initiator azobisisobutyronitrile 6 g, and heat for 3 h, filter, and obtain composite fiber magnetic particles, which are washed with pure water and ethanol and vacuum dried to constant weight.

[0104] (2) Hydrolysis modification of fiber composite magnetic particles

[0105] Add 100 g of dried fiber composite magnetic particles to a reactor, add 300 g of a sodium phosphate solution with a mass concentration of 12%, and use mechanical stirring to hydrolyze at 90°C for 6 h; filter to obtain hydrolyzed fiber composite magnetic particles, which are washed with pure water and ethanol and vacuum dried to constant weight.

[0106] (3) Biofilm formation and pollutant removal experiment of aerobic wastewater treatment system

[0107] In a 1000 mL activated sludge reactor, add 800 mL of aerobic activated sludge with a suspended solid content of 5000 mg / L, and add 3.6 g of hydrolyzed and modified fiber composite magnetic particles obtained in step (2). Control the gas flow to be 200 mL / min through a gas rotor flowmeter. Run in a sequencing batch mode, with 12 h as one cycle, 11 h of aeration per cycle, and 30 min of sedimentation. Perform drainage, water feeding, etc. for 30 min. Drain 500 mL each time, feed 490 mL, and initially add 10 mL of simulated wastewater concentrate per cycle, with an ammonia nitrogen concentration of 5 g / L and a COD concentration of 50 g / L. Run continuously for 10 days, measure the COD and ammonia nitrogen concentrations in the supernatant before drainage per cycle, measure the oxygen consumption rate of 50 mL of sludge after 10 days, and observe the aerobic activated sludge on the surface of the fiber composite magnetic particles after 10 days.

[0108] (4) Biofilm formation and pollutant removal experiment of anaerobic wastewater treatment system

[0109] In a 250 mL sequencing batch reactor, inoculate anaerobic activated sludge and hydrolysis modified fiber composite magnetic microparticles obtained in step (2) are added, and a intermittent stirring device is used for stirring, with a stirring frequency of 5 min stirring for 30 s, and the temperature is controlled at 35 ± 1 ℃. Run in a sequencing batch mode, 12 h as a cycle. Aeration for 11 h per cycle, settling for 30 min, and 30 min for drainage, water feeding, etc. Drainage of 100 mL each time, water feeding of 97.5 mL, and initial addition of 2.5 mL of simulated wastewater concentrate per cycle, wherein the simulated wastewater concentrate has a nitrate nitrogen concentration of 5 g / L and a COD concentration of 50 g / L. Run continuously for 30 days, take samples before drainage every day, test the settling performance of the anaerobic activated sludge and the COD removal effect, and observe the surface of the fiber composite magnetic microparticles after 30 days.

[0110] Example 8

[0111] (1) Preparation of fiber composite magnetic microparticles

[0112] Take 35 g of ferroferric oxide magnetic particles and add them to a 250 mL four-necked flask containing 100 g of pure water, ultrasonic treatment for 30 min, under nitrogen protection, at 55 ℃, use mechanical stirring for 30 min, add vinyltrichlorosilane 35 g and sodium dodecyl sulfate 0.1 g to the system, heat to 65 ℃, age for 2 h, then add a mixed solution of 75 g of styrene, 15 g of pentaerythritol triacrylate and 15 g of glycidyl methacrylate to the system, after the completion of the dropwise addition of the mixed solution, add 0.7 g of polypropylene fibers with a length of 350 μm and a diameter of 7 μm, stir uniformly, add initiator potassium persulfate 6 g, heat for 3 h, filter, obtain fiber composite magnetic microparticles, wash with pure water and ethanol, vacuum dry to constant weight.

[0113] (2) Hydrolysis modification of fiber composite magnetic microparticles

[0114] Add 100 g of dried fiber composite magnetic microparticles to the reactor, add 350 g of 5% mass concentration sodium sulfide solution, use mechanical stirring, hydrolyze at 80 ℃ high temperature for 0.5 h; filter, obtain hydrolyzed fiber composite magnetic microparticles, wash with pure water and ethanol, vacuum dry to constant weight.

[0115] (3) Biofilm formation and pollutant removal experiment of aerobic wastewater treatment system

[0116] In a 1000 mL activated sludge reactor, 800 mL of aerobic activated sludge with a suspended solid content of 5000 mg / L was added, 3.6 g of the hydrolysis-modified fiber-composite magnetic microparticles obtained in step (2) was added, and the gas flow was controlled at 200 mL / min by a gas rotameter. The reactor was operated in a sequencing batch mode, with 12 h as one cycle, 11 h of aeration, 30 min of sedimentation, and 30 min of water discharge and water feeding. Each time, 500 mL of water was discharged, 490 mL of water was fed, and 10 mL of simulated wastewater concentrate was added at the beginning of each cycle, with the ammonia nitrogen concentration of the simulated wastewater concentrate being 5 g / L and the COD concentration being 50 g / L. The reactor was continuously operated for 10 days, and the COD and ammonia nitrogen concentrations in the supernatant were measured before water discharge in each cycle. After 10 days, 50 mL of sludge was taken to measure the oxygen consumption rate, and the aerobic activated sludge on the surface of the fiber-composite magnetic microparticles was observed.

[0117] (4) Biofilm formation and pollutant removal in an anaerobic wastewater treatment system

[0118] In a 250 mL sequencing batch reactor, anaerobic activated sludge and the hydrolysis-modified fiber-composite magnetic microparticles obtained in step (2) were added, and a intermittent stirring device was used for stirring, with a stirring frequency of 30 s per 5 min, and the temperature was controlled at 35±1°C. The reactor was operated in a sequencing batch mode, with 12 h as one cycle. Each cycle included 11 h of aeration, 30 min of sedimentation, and 30 min of water discharge and water feeding. Each time, 100 mL of water was discharged, 97.5 mL of water was fed, and 2.5 mL of simulated wastewater concentrate was added at the beginning of each cycle, with the nitrate nitrogen concentration of the simulated wastewater concentrate being 5 g / L and the COD concentration being 50 g / L. The reactor was continuously operated for 30 days, and the settling performance and COD removal effect of the anaerobic activated sludge were tested before water discharge every day. After 30 days, the anaerobic activated sludge on the surface of the fiber-composite magnetic microparticles was observed.

[0119] Comparative Example 1

[0120] (1) Preparation of magnetic microparticles

[0121] The ferriferrous oxide polymer particles were prepared in the same manner as in step (1) of Example 1, except that the step of “adding 0.7 g of polyester fibers with a length of 350 μm and a diameter of 2 μm” was not included.

[0122] (2) Biofilm formation and pollutant removal in an aerobic wastewater treatment system

[0123] (3) Biofilm formation and pollutant removal in an anaerobic wastewater treatment system

[0124] Test methods and results:

[0125] Microscope observation: The prepared fiber composite magnetic microparticles, the hydrolysis modified magnetic microparticles, and the hydrolysis modified and metal ion chelated magnetic microparticles were dried, and then observed under a microscope. The fluorescent microscope pictures of the material samples are shown in FIGS. 1-3. Figure 2 and Figure 3 As shown in FIGS. 1-3, it can be found that the magnetic microspheres prepared in Example 1 have obvious fibrous structure, while the fibrous structure is not observed in the magnetic microspheres prepared in Comparative Example 1. That is, the method of Example 1 can successfully incorporate fibers into the magnetic microspheres, and make the surface of the microspheres have fibrous morphology.

[0126] Adsorption of activated sludge test: 1 g of sterilized biological filler sample was added into a 250 mL conical flask containing 100 mL of activated sludge suspension. Three parallel samples were set for each group. The test sample flask was placed in a shaking incubator at 37°C and 200 rpm. After 3 days of shaking, the magnetic microparticles were taken out for fluorescent staining. Under the same test conditions, the fluorescent microscope pictures of the material samples are shown in FIGS. 4-6. Figure 4 As shown in FIGS. 4-6, it can be found that the activated sludge adsorbed by Example 1 is obviously more than that of Comparative Example 1, and the fibrous protrusions on the microparticles of Example 1 have obviously stronger fluorescence intensity. That is, the incorporation of fibers is beneficial to adsorb more activated sludge.

[0127] Aerobic water treatment application test: The fiber composite magnetic microparticles of the example and the magnetic microparticles of the comparative example were placed in a biological reactor for biofilm formation and pollutant removal test in an aerobic sewage treatment system. The test scheme was consistent with step (2) of Example 1. The COD concentration and ammonia nitrogen concentration were tested by the corresponding reagent kit of Lianhua Technology Co., Ltd. The test results are shown in Table 1, taking only the data of the 10th day as an example.

[0128] Anaerobic water treatment application test: The fiber composite magnetic microparticles of the example and the magnetic microparticles of the comparative example were placed in a biological reactor for biofilm formation and pollutant removal test in an anaerobic sewage treatment system. The test scheme was consistent with step (3) of Example 1. The COD concentration was tested by the corresponding reagent kit of Lianhua Technology Co., Ltd. The nitrate nitrogen concentration was tested by ultraviolet spectrophotometry. The test results are shown in Table 1, taking only the data of the 30th day as an example.

[0129] Table 1 Water treatment test results of each example and comparative example

[0130]

[0131] From Table 1, it can be seen that the degradation rates of COD and ammonia nitrogen of the fiber composite magnetic microparticles are superior to those of the common magnetic microparticles in aerobic water treatment, and the biocompatibility of the fiber composite magnetic microparticles after hydrolysis modification and chelation of metal particles is improved, so that the degradation rates of COD and ammonia nitrogen are higher than those of the unmodified fiber composite magnetic microparticles; similarly, in anaerobic water treatment, the removal rates of COD and nitrate of the fiber composite magnetic microparticles are higher than those of the common magnetic microparticles, and the biocompatibility of the fiber composite magnetic microparticles after hydrolysis modification and chelation of metal particles is further improved, so that the degradation rates of COD and ammonia nitrogen are higher than those of the unmodified fiber composite magnetic microparticles.

[0132] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application, and those skilled in the art can make modifications to the embodiments without creative contribution according to the needs after reading the specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A method for preparing fiber-reinforced magnetic microparticles, characterized in that, Includes the following steps: (1) Add the magnetic particles of iron oxide to a reactor containing pure water, sonicate for 15-30 minutes, and homogenize by mechanical stirring under nitrogen protection. (2) Add modifier and surfactant to the system at 35-55℃ and age for 2 hours; (3) Then add a mixed monomer solution of styrene, crosslinking agent and epoxy monomer to the system dropwise; (4) After the above mixed monomer solution is added dropwise, the fiber is added and stirred evenly. The fiber diameter is 1-10 μm and the fiber length is 300-1000 μm. (5) After stirring evenly, add the initiator to the system, heat to 65-85℃, and keep warm for 3-6 hours with stirring; (6) Filtration was performed to separate the solid and liquid components, and the fiber composite magnetic microparticles were obtained. They were washed with pure water and ethanol and then vacuum dried to constant weight.

2. The method for preparing fiber composite magnetic microparticles according to claim 1, characterized in that, The mass ratio of the modifier to the magnetite particles is 1:1 to 1.5:

1.

3. The method for preparing fiber composite magnetic microparticles according to claim 1, characterized in that, Based on the total mass of the mixed monomer solution of styrene, crosslinking agent and epoxy monomer, the amount of styrene is 60-80%, the amount of crosslinking agent is 10-20%, and the amount of epoxy monomer is 10-20%.

4. A method for modifying fiber-reinforced magnetic microparticles, characterized in that, Includes the following steps: The dried fiber composite magnetic microparticles as described in any one of claims 1-3 are added to the reactor, a hydrolyzing agent is added to the system, and the system is hydrolyzed at 70-90°C using mechanical stirring for 0.5-6 hours. The mixture was filtered to obtain hydrolyzed modified fiber composite magnetic microparticles, which were washed with pure water and ethanol and then vacuum dried to constant weight.

5. The method according to claim 4, characterized in that, It also includes the following steps: Take the dried and hydrolyzed fiber composite magnetic microparticles and add them to the reactor. Add metal salt solution to the system and stir at room temperature for 2-5 hours. The mixture was filtered to obtain hydrolyzed and chelated metal ions-containing fiber composite magnetic microparticles, which were then washed with pure water and ethanol and vacuum dried to constant weight.

6. The method according to claim 4, characterized in that, The hydrolysing agent includes one or more of sodium hydroxide, potassium hydroxide, water glass, sodium phosphate, potassium phosphate, and sodium sulfide, and the mass concentration of the hydrolysing agent is 1-20%.

7. The method according to claim 5, characterized in that, The metal salt solution includes one or more of ferric chloride, ferric sulfate, ferrous chloride, ferrous sulfate, copper chloride, copper sulfate, nickel chloride, nickel sulfate, manganese chloride, and manganese sulfate. The mass concentration of the metal salt solution is 1-20%, and the mass ratio of the metal salt solution to the fiber composite magnetic particles is (200-5):

1.

8. The application of fiber composite magnetic microparticles or modified microparticles as described in any one of claims 1-7 as a carrier in the treatment of wastewater in an aerobic activated sludge reactor, characterized in that, Includes the following steps: 1) Add 1-20 g / L of aerobic activated sludge and 1-20 g / L of fiber composite magnetic microparticles or their modified microparticles to the activated sludge reactor, and control the air flow rate to 200 mL / min using a gas rotor flow meter; 2) The system operates in a sequential batch process, with a 12-hour cycle. Each cycle consists of 11 hours of aeration, 30 minutes of settling, and 30 minutes of drainage and water intake. Each time, 500 mL of supernatant is discharged, and 490 mL of tap water and 10 mL of simulated wastewater concentrate are added. The simulated wastewater concentrate is prepared with ammonium chloride and sodium acetate, and has an ammonia nitrogen concentration of 5 g / L and a COD concentration of 50 g / L. 3) Run continuously for 10 days. Before each drainage cycle, take a sample to measure the COD and ammonia nitrogen concentrations in the supernatant. After 10 days, take 50 mL of sludge to measure the oxygen consumption rate. After 10 days, observe the aerobic activated sludge on the surface of fiber composite magnetic microparticles or their modified microparticles. The COD removal rate is ≥90% and the ammonia nitrogen removal rate is ≥90%.

9. The application of fiber composite magnetic microparticles or modified microparticles as described in any one of claims 1-7 as a carrier in the treatment of wastewater in an anaerobic activated sludge reactor, characterized in that, Includes the following steps: 1) In a sequencing batch reactor, add anaerobic activated sludge at a concentration of 5-40 g / L and fiber composite magnetic microparticles or their modified microparticles at a concentration of 1-15 g / L. Use an intermittent stirring device to stir at a frequency of 5 min for 30 s, and control the temperature at 35±1℃. 2) The system operates in a sequential batch process, with each cycle lasting 12 hours. Each cycle consists of 11 hours of aeration, 30 minutes of settling, and 30 minutes of drainage and water intake. Each time, 100 mL of supernatant is discharged, and 97.5 mL of tap water and 2.5 mL of simulated wastewater concentrate are added. The simulated wastewater concentrate is prepared from potassium nitrate and sodium acetate, and has a nitrate nitrogen concentration of 5 g / L and a COD concentration of 50 g / L. 3) Run continuously for 30 days, take samples before draining each day to test the settling performance and COD removal effect of anaerobic activated sludge. After 30 days, observe the anaerobic activated sludge on the surface of fiber composite magnetic microparticles or their modified microparticles. The COD removal rate is ≥90% and the nitrate nitrogen removal rate is ≥90%.

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